This invention concerns a wheeled conveyance, and particularly but not exclusively a manually pushable wheeled conveyance, and especially a wheelchair.
Problems are often encountered with wheelchairs and similar conveyances when climbing a step or onto a curb. Whilst is generally relatively easy to raise the front wheel of the wheelchair to locate it on a step, difficulties are often encountered, and particularly when a heavy person is carried, in subsequently pushing the wheelchair up the step. Difficulties can also be encountered by wheelchair users when transferring from a wheelchair to an adjacent car. This is particularly due to the generally large rear wheel of the wheelchair which comes between a user and a car such that the user has to manoeuvre around the wheel.
According to the present invention there is provided a wheeled conveyance, the conveyance comprising a first main wheel arrangement which is located towards the in use rear of the conveyance, a second wheel arrangement slidably movable between a first conventional position in front of the main wheel arrangement and a second more rearward position wherein the second wheel arrangement is lower than the first wheel arrangement to be ground engageable in preference to the first wheel arrangement.
The conveyance preferably comprises a ground engaging member, which desirably comprises a third wheel arrangement, and is located towards the front of the conveyance. The ground engaging member is preferably arranged so as to be ground engageable at least when the second wheel arrangement is in the second position. The ground engaging member is preferably arranged to be generally clear of the ground when the second wheel arrangement is in the first position.
Any or all of the first, second and third wheel arrangements preferably comprise a pair of wheels, with each of the pair located towards a respective side of the conveyance.
The conveyance preferably comprises a frame upon which the wheel arrangements are mounted.
The second wheel arrangement is preferably slidably mounted on a track, which track is mounted on the frame. The track is preferably pivotally mounted on the frame and movable between a first condition aligned generally horizontally or upwardly inclined towards the rear of the conveyance, and a second condition inclined downwardly towards the rear of the conveyance.
Means are preferably provided for locking the track in the second condition. The locking means may be arranged to be automatically disengaged upon the second wheel arrangement reaching the second position.
The locking means may comprise a ratchet member engageable with a pivoted sprung member, and against which sprung member the second wheel arrangement is preferably engageable to cause disengagement of the locking arrangement.
The track may be urged towards the first condition. The track may be pivotally mounted on the frame at a point towards the front of the frame, and a first resilient means may extend between the track and the frame at a location on the frame spaced from the pivotal mounting so as to urge the track towards the first condition.
The second wheel arrangement may be urged towards to the first position, and the urging may be greater when the track is in the second condition.
Alternatively the track may be pivotally mounted on an arrangement which is movably mounted on the frame. The mounting arrangement may be pivotally mounted on the frame, and/or of variable length. First locking means may be provided for locking the arrangement against pivotal movement on the frame. Second locking means may be provided for locking the length of the arrangement.
The first and/or second locking means are preferably operable by a foot pedal, which pedal preferably permits the track to be pivoted as required.
The second wheel arrangement may be connected to the frame via a second resilient means to provide said urging of said arrangement towards the first position. An actuating member may be provided connected to the track, and engageable by a person pushing the conveyance to move the track into the second condition. The actuating member preferably extends rearwardly from the conveyance. The actuating member may be operable by a person""s foot. The actuating member may comprise a plate, which may be foldable, and/or which may have a generally chevron shape in plan view.
The second resilient means may be mounted on the actuating member such that the resilient means is stretched further away from a relaxed position when the track is moved to the second condition.
An end of the second resilient means spaced from the actuating member may slidably mount line means which extends from a first point towards the front of the frame via said slidable mounting on the second resilient means, to a slidable mounting at a second point towards the front of the frame, to connect to the second wheel arrangement. Alternatively a further resilient means may mount said line means.
Means may be provided for locking the second wheel arrangement in the first position, and said locking means may be automatically actuable upon the second wheel arrangement moving to the first position. The locking means may comprise a sprung finger.
Means are preferably provided for selectively releasing the locking means, and said release means may be operable by a person pushing the conveyance. Said release means may comprise line means extending from the sprung finger to a handle.
Where the second wheel arrangement comprises a pair of wheels, a respective track and other corresponding components are preferably provided for each wheel. Where a pair of actuating members are provided, an engagement member is preferably provided extending therebetween. Where the conveyance is collapsible a hinge or other arrangement may be provided in said engagement member to permit folding thereof.
The conveyance frame preferably comprises two parts which are selectively braced apart in an in use condition. A seating arrangement is preferably provided which is selectively mountable on the frame. The seating arrangement is preferably substantially rigid at least in a transverse direction to brace the frame parts apart. The seating arrangement preferably comprises a base, back, and desirably also arm rests, and means for retaining said components in required relative positions. The seating arrangement preferably also provides handles for the conveyance, which handles may be integral with the arm rests.
The invention further provides a wheelchair in the form of a conveyance with a two part frame according to any of the features of the above paragraph.
The invention also provides a wheelchair in the form of a conveyance according to any of the preceding nineteen paragraphs.
Preferably at least the first and second wheel arrangements respectively comprise a pair of spaced wheels.
Each track and respective actuation member are preferably co-existensive, and foot rests preferably extend from the front of each of the tracks. The ground engagement member preferably comprises a pair of third wheels, and each third wheel is preferably mounted on a respective foot rest and to extend therebeneath. The tracks are preferably pivotally mounted to the frame, and generally at the connection between the tracks and the foot rests such that upon the tracks being moved to the second condition the foot rests are raised up.
In a particular embodiment, the first wheels are releasably mountable on the frame. Power means may be provided for moving the second wheels, which power means may be actuable by a person on the wheelchair.